Develop Reference

Deleting a user from Azure Active Directory B2C Android/Java

I have an Android application in which I'm using Azure AD B2C to authenticate users. Users login and logout of the application as needed. I would like to give the user the option to delete their own account.
I understand that I need to use the Azure AD Graph API to delete the user. This is what I have so far:
According to this link, it looks like deleting a user from a personal account (which is what the B2C users are using) is not possible. Is that correct?
Here's my code snippet for the Graph API call. Feel free to ignore it if I'm off track and there is a better way to solve this.
I believe I need a separate access token than what my app currently has (as the graph API requires other API consent). So, I'm getting the access token as follows:
AcquireTokenParameters parameters = new AcquireTokenParameters.Builder()
.startAuthorizationFromActivity(getActivity())
.fromAuthority(B2CConfiguration.getAuthorityFromPolicyName(B2CConfiguration.Policies.get("SignUpSignIn")))
.withScopes(B2CConfiguration.getGraphAPIScopes())
.withPrompt(Prompt.CONSENT)
.withCallback(getGraphAPIAuthCallback())
.build();
taxApp.acquireToken(parameters);
In the getGraphAPIAuthCallback() method, I'm calling the Graph API using a separate thread (in the background):
boolean resp = new DeleteUser().execute(authenticationResult.getAccessToken()).get();
Finally, in my DeleterUser() AsyncTask, I'm doing the following:
#Override
protected Boolean doInBackground(String... aToken) {
final String asToken = aToken[0];
//this method will be running on background thread so don't update UI from here
//do your long running http tasks here,you dont want to pass argument and u can access the parent class' variable url over here
IAuthenticationProvider mAuthenticationProvider = new IAuthenticationProvider() {
#Override
public void authenticateRequest(final IHttpRequest request) {
request.addHeader("Authorization",
"Bearer " + asToken);
}
};
final IClientConfig mClientConfig = DefaultClientConfig
.createWithAuthenticationProvider(mAuthenticationProvider);
final IGraphServiceClient graphClient = new GraphServiceClient.Builder()
.fromConfig(mClientConfig)
.buildClient();
try {
graphClient.getMe().buildRequest().delete();
} catch (Exception e) {
Log.d(AccountSettingFragment.class.toString(), "Error deleting user. Error Details: " + e.getStackTrace());
}
return true;
}
Currently, my app fails when trying to get an access token with a null pointer exception:
com.microsoft.identity.client.exception.MsalClientException: Attempt to invoke virtual method 'long java.lang.Long.longValue()' on a null object reference
Any idea what I need to do to provide the user the option to users to delete their own account? Thank you!

Thanks for the help, #allen-wu. Due to his help, this azure feedback request and this azure doc, I was able to figure out how to get and delete users silently (without needing intervention).
As #allen-wu stated, you cannot have a user delete itself. So, I decided to have the mobile app call my server-side NodeJS API when the user clicks the 'Delete Account' button (as I do not want to store the client secret in the android app) and have the NodeJS API call the Azure AD endpoint to delete the user silently. The one caveat is that admin consent is needed the first time you try to auth. Also, I have only tested this for Graph API. I'm not a 100% sure if it works for other APIs as well.
Here are the steps:
Create your application in your AAD B2C tenant. Create a client secret and give it the following API permissions: Directory.ReadWrite.All ;
AuditLog.Read.All (I'm not a 100% sure if we need the AuditLog permission. I haven't tested without it yet).
In a browser, paste the following link:
GET https://login.microsoftonline.com/{tenant}/adminconsent?
client_id=6731de76-14a6-49ae-97bc-6eba6914391e
&state=12345
&redirect_uri=http://localhost/myapp/permissions
Login using an existing admin account and provide the consent to the app.
Once you've given admin consent, you do not have to repeat steps 1-3 again. Next, make the following call to get an access token:
POST https://login.microsoftonline.com/{B2c_tenant_name}.onmicrosoft.com/oauth2/v2.0/token
In the body, include your client_id, client_secret, grant_type (the value for which should be client_credentials) and scope (value should be 'https://graph.microsoft.com/.default')
Finally, you can call the Graph API to manage your users, including deleting them:
DELETE https://graph.microsoft.com/v1.0/users/{upn}
Don't forget to include the access token in the header. I noticed that in Postman, the graph api had a bug and returned an error if I include the word 'Bearer' at the start of the Authorization header. Try without it and it works. I haven't tried it in my NodeJS API yet, so, can't comment on it so far.
#allen-wu also suggested using the ROPC flow, which I have not tried yet, so, cannot compare the two approaches.
I hope this helps!

There is a line of code: graphClient.getUsers("").buildRequest().delete();
It seems that you didn't put the user object id in it.
However, we can ignore this problem because Microsoft Graph doesn't allow a user to delete itself.
Here is the error when I try to do it.
{
"error": {
"code": "Request_BadRequest",
"message": "The principal performing this request cannot delete itself.",
"innerError": {
"request-id": "8f44118f-0e49-431f-a0a0-80bdd954a7f0",
"date": "2020-06-04T06:41:14"
}
}
}

How to test service calls using mockwebserver that contains redirection?

I am using mockwebserver to mock request and response for my android app. I am testing a login feature which goes through a series of 4 service calls.
Get access token
Re-direct
Get user info (different base url)
Get some other stuff (original base url)
I am trying to mock the response of the redirected call. Here is my code:
#Test
public void testSuccessfulLogin() throws Exception {
// Post
server.enqueue(new MockResponse()
.setResponseCode(HTTP_OK)
.setBody(getStringFromFile(getInstrumentation().getContext(), "access_token.json")));
// Redirect
server.enqueue(new MockResponse().setResponseCode(HTTP_MOVED_TEMP));
// GET user info
server.enqueue(new MockResponse().setResponseCode(HTTP_OK).setBody(getStringFromFile(getInstrumentation().getContext(), "userinfo.json")));
// GET some other stuff
server.enqueue(new MockResponse().setResponseCode(HTTP_OK)
.setBody(getStringFromFile(getInstrumentation().getContext(), "sts.json")));
// Init call
loginWithoutWaiting(Data.serviceLoginUsername, Data.serviceLoginPassword);
// Debug (need to loop 4 times to get all 4 call paths)
RecordedRequest request = server.takeRequest();
request.getPath();
}
My test fails at the Redirect code. I cannot login. I have found some hints here but I do not fully understand what is going on, thus can't make it work at the moment.

It turned out to be quite easy. In the call that makes redirect, create a new mocked response with response code 302 and header with location url. The next call will use that location url.
case "/userinfo":
return new MockResponse().setResponseCode(HTTP_MOVED_TEMP).setHeader("Location", "/api-test.com/users");
case "/api-test.com/users":
return new MockResponse().setBody("{}")).setResponseCode(HTTP_OK);

Consume WebAPI2 site from Android client with Google Authentication

I've been wracking my brain these past two days to try and understand how to use the authentication built into ASP.NET's WebAPI 2 using Google as an external authentication, and not being familiar with OAuth 2, I'm quite lost. I have followed this tutorial to set up the sign-in button on my Android client and send the "idToken" to the Web API. I've also followed this (now out of date) tutorial on setting up Google as an external login.
The problem happens when I try to send it I get {"error":"unsupported_grant_type"} as a response. Some other tutorials lead me to believe that the POST to mysite.com/token does not contain the correct data. This means I'm either building the request incorrectlyon the client, I'm somehow handling it incorrectly on the backend, I'm sending it to the wrong url, or I'm doing something entirely else wrong.
I found this SO answer which says to get a URL from /api/Accounts/ExternalLogins, but the sign-in button already gives me the access token that would supply to me (if I understand that correctly).
If someone could help me out here on what the exact process should be from start to finish, that would be amazing.
UPDATE: Okay, so here are some things that I've learned since I asked this question.
website.com/token URI is the redirect for the built in OAuth server in the WebAPI2 template. This is not useful for this particular problem.
The id_token is an encoded JWT token.
The website.com/signin-google URI is the redirect for normal Google login, but does not accept these tokens.
I may have to write my own AuthenticationFilter that uses the Google Client library to authorize through the Google API.
UPDATE 2: I'm still working on getting this AuthenticationFilter Implementation. Things seem to be going well at this point, but I'm getting stuck on some things. I've been using this example to get the token verification code, and this tutorial to get the AuthenticationFilter code. The result is a mix of both of them. I'll post it here as an answer once it's complete.
Here are my current problems:
Producing an IPrincipal as output. The verification example makes a ClaimPrincipal, but the AuthenticationFilter example code uses a UserManager to match the username to an existing user and returns that principal. The ClaimsPrincipal as created in the verification example directly does not auto-associate with the existing user, so I need to attempt to match some element of the claims to an existing user. So how do I do that?
I still have an incomplete idea of what a proper flow for this is. I'm currently using the Authentication header to pass my id_token string using a custom scheme: "goog_id_token". The client must send their id_token for every method called on the API with this custom AuthenticationFilter. I have no idea how this would usually be done in a professional environment. It seems like a common enough use case that there would be tons of information about it, but I haven't seen it. I have seen the normal OAuth2 flow, and since I'm only using an ID Token, and not an Access Token I'm a bit lost on what an ID Token is supposed to be used for, where it falls in a flow, and where it's supposed to live in an HTTP packet. And because I didn't know these things, I've kind of been making it up as I go along.

Wow, I did it. I figured it out. I... I can't believe it.
As metioned in my question Update 2, this code is assembled from Google's official API C# example and Microsoft's Custom AuthenticationFilter tutorial and code example. I'm going to paste the AuthorizeAsync() here and go over what each block of code does. If you think you see an issue, please feel free to mention it.
public async Task AuthenticateAsync(HttpAuthenticationContext context, CancellationToken cancellationToken)
{
bool token_valid = false;
HttpRequestMessage request = context.Request;
// 1. Look for credentials in the request
//Trace.TraceInformation(request.ToString());
string idToken = request.Headers.Authorization.Parameter.ToString();
The client adds the Authorization header field with the scheme followed by a single space, followed by the id token. It looks something like Authorization: id-token-goog IaMS0m3.Tok3nteXt.... Putting the ID token in the body as given in the google documentation made no sense in this filter so I decided to put it in the header. For some reason it was difficult to pull custom headers from the HTTP packets so I just decided to use the Authorization header with a custom scheme followed by the ID token.
// 2. If there are no credentials, do nothing.
if (idToken == null)
{
Trace.TraceInformation("No credentials.");
return;
}
// 3. If there are credentials, but the filter does not recognize
// the authentication scheme, do nothing.
if (request.Headers.Authorization.Scheme != "id-token-goog")
// Replace this with a more succinct Scheme title.
{
Trace.TraceInformation("Bad scheme.");
return;
}
This whole point of a filter is to ignore requests that the filter doesn't govern (unfamiliar auth schemes, etc), and make judgement on requests that it's supposed to govern. Allow valid authentication to pass to the downstream AuthorizeFilter or directly to the Controller.
I made up the scheme "id-token-goog" because I had no idea if there was an existing scheme for this use case. If there is, somebody please let me know and I'll fix it. I guess it doesn't particularly matter at the moment as long as my clients all know the scheme.
// 4. If there are credentials that the filter understands, try to validate them.
if (idToken != null)
{
JwtSecurityToken token = new JwtSecurityToken(idToken);
JwtSecurityTokenHandler jsth = new JwtSecurityTokenHandler();
// Configure validation
Byte[][] certBytes = getCertBytes();
Dictionary<String, X509Certificate2> certificates =
new Dictionary<String, X509Certificate2>();
for (int i = 0; i < certBytes.Length; i++)
{
X509Certificate2 certificate =
new X509Certificate2(certBytes[i]);
certificates.Add(certificate.Thumbprint, certificate);
}
{
// Set up token validation
TokenValidationParameters tvp = new TokenValidationParameters()
{
ValidateActor = false, // check the profile ID
ValidateAudience =
(CLIENT_ID != ConfigurationManager
.AppSettings["GoogClientID"]), // check the client ID
ValidAudience = CLIENT_ID,
ValidateIssuer = true, // check token came from Google
ValidIssuer = "accounts.google.com",
ValidateIssuerSigningKey = true,
RequireSignedTokens = true,
CertificateValidator = X509CertificateValidator.None,
IssuerSigningKeyResolver = (s, securityToken, identifier, parameters) =>
{
return identifier.Select(x =>
{
// TODO: Consider returning null here if you have case sensitive JWTs.
/*if (!certificates.ContainsKey(x.Id))
{
return new X509SecurityKey(certificates[x.Id]);
}*/
if (certificates.ContainsKey(x.Id.ToUpper()))
{
return new X509SecurityKey(certificates[x.Id.ToUpper()]);
}
return null;
}).First(x => x != null);
},
ValidateLifetime = true,
RequireExpirationTime = true,
ClockSkew = TimeSpan.FromHours(13)
};
This is all unchanged from the Google example. I have almost no idea what it does. This basically does some magic in creating a JWTSecurityToken, a parsed, decoded version of the token string, and sets up the validation parameters. I'm not sure why the bottom portion of this section is in it's own statement block, but it has something to do with the CLIENT_ID and that comparison. I'm not sure when or why the value of CLIENT_ID would ever change, but apparently it's necessary...
try
{
// Validate using the provider
SecurityToken validatedToken;
ClaimsPrincipal cp = jsth.ValidateToken(idToken, tvp, out validatedToken);
if (cp != null)
{
cancellationToken.ThrowIfCancellationRequested();
ApplicationUserManager um =
context
.Request
.GetOwinContext()
.GetUserManager<ApplicationUserManager>();
Get the user manager from the OWIN context. I had to dig around in context intellisense until I found GetOwinCOntext(), and then found that I had to add using Microsoft.Aspnet.Identity.Owin; in order to add the partial class that included the method GetUserManager<>().
ApplicationUser au =
await um
.FindAsync(
new UserLoginInfo(
"Google",
token.Subject)
);
This was the very last thing I had to fix. Again, I had to dig through um Intellisense to find all of the Find functions and their overrides. I had noticed from the Identity Framework-created tables in my database that there is one called UserLogin, whose rows contain a provider, a provider key, and a user FK. The FindAsync() takes a UserLoginInfo object, which contains only a provider string and a provider key. I had a hunch that these two things were now related. I had also recalled that there was a field in the token format that included a key-looking field that was a long number that started with a 1.
validatedToken seems to be basically empty, not null, but an empty SecurityToken. This is why I use token instead of validatedToken. I'm thinking there must be something wrong with this, but since the cp is not null, which is a valid check for a failed validation, it makes enough sense that the original token is valid.
// If there is no user with those credentials, return
if (au == null)
{
return;
}
ClaimsIdentity identity =
await um
.ClaimsIdentityFactory
.CreateAsync(um, au, "Google");
context.Principal = new ClaimsPrincipal(identity);
token_valid = true;
Here I have to create a new ClaimsPrincipal since the one created above in validation is empty (apparently that's correct). Took a guess on what the third parameter of CreateAsync() should be. It seems to work that way.
}
}
catch (Exception e)
{
// Multiple certificates are tested.
if (token_valid != true)
{
Trace.TraceInformation("Invalid ID Token.");
context.ErrorResult =
new AuthenticationFailureResult(
"Invalid ID Token.", request);
}
if (e.Message.IndexOf("The token is expired") > 0)
{
// TODO: Check current time in the exception for clock skew.
Trace.TraceInformation("The token is expired.");
context.ErrorResult =
new AuthenticationFailureResult(
"Token is expired.", request);
}
Trace.TraceError("Error occurred: " + e.ToString());
}
}
}
}
The rest is just exception catching.
Thanks for checking this out. Hopefully you can look at my sources and see which components came from which codebase.

Authenticate android app to call web api service

I have an android app that have a login form for student, and I want to check the student credential at web api depending on the stored data in sql server
I have searched the web and watch many videos that talking about many scenarios and nothing helped me.
All I want is a custom validation for my rest service (so I should send the credential for each request)
What should I do at asp.net web api service
how I can implement that at android application

Seems you didn't search for "Web API Token Based Authentication" ;) Anyhow what you need to implement is very simple.
You need to use OAuth 2.0 Resource Owner Credentials Flow which means that you want to provide the username/password only once for a specific endpoint i.e(/token) and then you if the username/password valid you obtain something called Bearer Access Token.
This token is valid for specified period and you can configure this in your Web API.
Once you obtain the access token, you need to store it securely in your android app, then you keep sending it with each request to your web api protected end points using the Authorization header (Bearer scheme(.
I've written very detailed post which covers your scenario 100%. Please check the post Token Based Authentication and let me know if you need further help.

I have used basic authentication for security,so I should provide the base64 encoding of
username:password
in header for each request as the following
authorization: Basic 'encoded username:password
httpGet.setHeader("Authorization", "Basic "+encodeUsernameAndPassword());
At the server side I have implemented message handler
public class BasicAuthenticationHandler : DelegatingHandler
{
public readonly IAuthenticationService authService;
public BasicAuthenticationHandler(IAuthenticationService service)
{
this.authService = service;
}
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
AuthenticationHeaderValue authHeader = request.Headers.Authorization;
if (authHeader == null || authHeader.Scheme != "Basic")
{
return Unauthorized(request);
}
string encodedCredentials = authHeader.Parameter;
var credentialsBytes = Convert.FromBase64String(encodedCredentials);
var credentials = Encoding.ASCII.GetString(credentialsBytes).Split(':');
if (!authService.Authenticate(credentials[0], credentials[1]))
{
return Unauthorized(request);
}
string[] roles = null;//todo
IIdentity identity = new GenericIdentity(credentials[0], "Basic");
IPrincipal user = new GenericPrincipal(identity, roles);
HttpContext.Current.User = user;
return base.SendAsync(request, cancellationToken);
}

Login in twice when using SyncAdapters

I am creating a new Android app using SyncAdapter to handle db sync.
I have everything in place and the app is working fine but I noticed that I am logged in twice.
The first login takes place when the AuthenticatorActivity class (it extends AccountAuthenticatorActivity) validates the user and password.
If the user and password are correct the AuthenticatorActivity then does:
If the account didn't exist it creates it using mAccountManager.addAccountExplicitly()
The authToken is saved using intent.putExtra(AccountManager.KEY_AUTHTOKEN, authToken);
This was basically copied/pasted from the Android samples, so I guess it's ok.
The issue is that when the SyncAdapter launches and uses
authtoken = mAccountManager.blockingGetAuthToken(account,
AuthenticatorActivity.PARAM_AUTHTOKEN_TYPE, true);
The getAuthToken() method inside the Authenticator class which extends AbstractAccountAuthenticator is called. And inside this method I am hitting the login endpoint once again.
From that point onwards the login endpoint is not hit again until the authToken expires.
This is not something that bothers me a lot but I would like to know if there is a way to avoid doing the login twice.

As you've seen, though Authenticator.java in the SampleSyncAdapter says
The interesting thing that this class demonstrates is the use of authTokens as part of the authentication process. ... If we already have an authToken stored in the account, we return that authToken. If we don't, but we do have a username and password, then we'll attempt to talk to the sample service to fetch an authToken.
that's a lie. Authenticator.getAuthToken doesn't to any cache checking, it just hits the network to get a token.
The solution is to add in the missing check:
Authenticator.java:
#Override
public Bundle getAuthToken(AccountAuthenticatorResponse response, Account account,
String authTokenType, Bundle loginOptions) throws NetworkErrorException {
// check that authToken type supported
...
// Check if we already have a cached token to return
final AccountManager am = AccountManager.get(mContext);
String cachedAuthToken = am.peekAuthToken(account, authTokenType);
if (cachedAuthToken != null) {
final Bundle result = new Bundle();
result.putString(AccountManager.KEY_ACCOUNT_NAME, account.name);
result.putString(AccountManager.KEY_ACCOUNT_TYPE, Constants.ACCOUNT_TYPE);
result.putString(AccountManager.KEY_AUTHTOKEN, cachedAuthToken);
return result;
}
// Get new authToken from server
...
// If all else fails, prompt the user for credentials
...
}
Note that the rest of your project needs to religiously use AccountManager.invalidateAuthToken when calls fail or else you'll wind up with an infinite loop of calls failing, trying to get a new auth token, and then failing again when the same cached auth token is returned.